Radiation sensitive polymers

ABSTRACT

RADIATION (THERMAL AND LIGHT)-SENSITIVE POLYMERS ARE PROVIDED AND ARE CHARACTERIZED BY (1) A RECURRING UNIT OF THE FORMULA:   -CH(-X)-CH(-Y)-CH(-R2)-CH2-   WHEREIN R2 IS LOWER-ALKOXY OR PHENYL, ONE OF X AND Y IS -COOR AND THE OTHER IS -COR1, R IS AND AZIDOSULFONYLCARBANILYLOXY ALKYLENE GROUP AND R1 IS -O-DYE, -NH-DYE OR HYDROXYARYLAMINO, OR (2) A COMBINATION IN THE SAME POLYME CHAIN OF RECURRING UNITS HAVING THE FORMULAE:   -CH(-X1)-CH(-Z1)-CH(-R2)-CH2-   WHEREIN ONE OF X1 AND Z1 REPRESENTS -COOH AND THE OTHER REPRESENTS -COOR AS DEFINED ABOVE, AND   -CH(-X2)-CH(-Z2)-CH(-R2)-CH2-   WHEREIN ONE OF X2 AND Z2 REPRESENTS -COOH AND THE OTHER REPRESENTS -COR1 AS REFINED ABOVE. THE POLYMERS CAN BE CHEMICALLY BONDED TO SUBSTRATES, SUCH AS THOSE CONTAINING C-H BONDS ONLY (E.G. POLYOLEFINS), WHICH ARE NOT NORMALLY DYE RECEPTIVE. THE BONDING IS EFFECTED BY EXPOSURE TO APPROPRIATE RADIATION; THE EXPOSURE CAN BY CARRIED OUT IMAGEWISE TO PRODUCE AN APPROPRIATE IMAGE ON THE SUBSTRATE. ACCORDINGLY, THE POLYMERS OF THE INVENTION FIND USE IN THE PHOTORESIST, PRINTING AND LIKE ARTS.

United States Patent US. Cl. 260-47 CZ 3 Claims ABSTRACT OF DISCLOSURERadiation (thermal and light)-sensitive polymers are provided and arecharacterized by- (1) a recurring unit of the formula:

wherein R is lower-alkoxy or phenyl, one of X and Y a wherein one of Xand 2; represents COOH and the other represents COR as defined above.The polymers can be chemically bonded to substrates, such as thosecontaining CH bonds only (e.g. polyolefins), which are not normally dyereceptive. The bonding is effected by exposure to appropriate radiation;the exposure can be carried out imagewise. to produce an appropriateimage on the substrate. Accordingly, the polymers of the invention finduse in the photoresist, printing and like arts.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is acontinuation-in-part of our copending application Ser. No. 39,178, filedMay 20, 1970 and now abandoned.

BACKGROUND OF THE INVENTION (1) Field of the invention This inventionrelates to novel radiation-sensitive polymers and is more particularlyconcerned with radiationsensitive polymers having attached to the chainthereof both dyestuif moieties and azidosulfonylcarbanilylalkoxycarbonylmoieties; and with the bonding of said polymers to substrates.

(2) Description of the prior art 3,699,080 Patented Oct. 17, 1972SUMMARY OF THE INVENTION The present invention comprises aradiation-sensitive polymer characterized by the presence of recurringunits selected from the class consisting of (a) a recurring unit of theformula:

wherein R is selected from the group consisting of loweralkoxy andphenyl, one of X and Y is COOR and the other COR R is a group of theformula: I t p E]: (SO2N3): A--0 NH- wherein A is alkylene having from 2to 6 carbon atoms separating the valencies and a total carbon atomcontent of from 2 to 10, R is selected from the class consisting oflower-alkyl and halogen, x is an integer from 1 to 2, y is an integerfrom 0 to 2, provided that x+y is not greater than 3, and the SO N groupis in any of positions 3, 4, and 5 in the phenyl nucleus to which it isattached, and at least one of the said positions 3, 4, and 5 isunsubstituted;

R is selected from the class consisting of the residue obtained byremoving the hydrogen atom from the hydroxyl group of a dyestuif havinga primary hydroxyl group, the residue obtained by removing the hydrogenatom from the amino group of a primary amino-containing dyestuff, andthe residue obtained by removing a hydrogen atom from the amino group ofan azo coupler; and

(b) a combination in the same polymer chain of recurring units havingthe formulae:

Li. a. T (11) wherein one of X and Z is COOH and the other is COOR asdefined above and Li ia Z l (III) wherein one of X and Z is COOH and theother is COR as defined above, and wherein R in each instance has themeaning defined above.

The invention also comprises a process for chemically bonding a dyestuitto a substrate which process comprises applying a radiation-sensitivepolymer, as defined above, to the substrate and exposing the treatedsubstrate to radiation which activates the radiation-sensitive polymerSo far as is known, the polymers of the invention are a novel and arenot analogous to any polymers hitherto known in the art. The use of thepolymers of the invention in bonding of dyes to substrates is alsobelieved to be novel and not analogous to processes hitherto known inthe art. I

and effects bonding between the radiation-sensitive polymer and thesubstrate.

The term alkylene having 2 to 6 carbon atoms separating the valenciesand a total carbon atom content from 2 to 10 means a divalent aliphatichydrocarbon radical having the stated carbon atom content in the chainseparating the valencies and overall. Illustrative of such radicals areethylene, 1,2-propylene, 1,3-propylene, 1,4- butylene, 1,2-pentylene,1,3-hexylene, 2,2-dimethyl-l,3- propylene, 2-methyl-l,4-butylene,3-methyl-l,2-pentylene, 2-ethyl-1,2-octylene and the like.

The term lower-alkyl means alkyl from 1 to 6 carbon atoms, inclusive,such as methyl, ethylpropyl, butyl, pentyl, hexyl, and isomeric formsthereof. The term lower-alkoxy means alkoxy from 1 to 6 carbon atoms,in-

'oxy,"hexyloxy, and isomeric forms thereof. The term halogen is employedin its usually accepted sense as being inclusive of fluorine, chlorine,bromine, and iodine The term radiation-sensitive is used herein toindicate that the polymers of the invention can be activated and undergomolecular modification on exposure to thermal and/ or actinic radiation.

The term azo coupler is used in its conventionally accepted sense inthedyestuff art as meaning an aminophenol to which'a diazonium compoundwill couple to form a dyestuif; see Encyclopedia of Chemical Technology,Ed. Kirk-Othmer, Second Edition, 1963, vol. 2,

p. 870 et seq. illustrative of azo couplers are p-amino- "phenol, 2amino l naphthol, 4 amino-l-naphthol,

fi-amino-l-naphthol and the like.

DETAILED DESCRIPTION OF THE INVENTION The radiation-sensitive polymersof the invention are characterized. in that they are derived from apolymer having the recurring,anhydride-containing unit:

wherein R is as hereinbefore defined, by modifying two more of the unitshaving the Formula I, it is not necessary that it also contain anyrecurring units of Formula II or III, although it can do so. However,where the radiation-sensitive polymer of the invention does not containany recurring units of Formula I said polymer contains a combination ofrecurring units of both Formula II and Formula III. The distribution ofsaid recurring units of Formulae I, H, and III and of any unchangedunits of Formula IV, in the polymer chain of the polymers of theinvention is entirely random as will be apparent from the variousmethods of preparation of the polymers which will be described below.

The polymers having the recurring unit (IV), which are employed asstarting materials in preparing the radiation-sensitive polymers of theinvention, are well-known in the art and are copolymers of maleicanhydride with styrene or the appropriate lower-alkyl vinyl ether. In};

preparing the radiation-sensitive polymers of'the invention in whichthere is a combination of recurring units (II) and (III). in the polymerchain, the preferred method comprises reacting the starting polymer witha mixture of the appropriate alcohol R-OH, wherein R is as hereinbeforedefined, and the appropriate amino-orhydroxy-containing dyestufl? or azocoupler R H,wherein R is as hereinbefore defined. The reaction iscarried out in the presence of a tertiary base and, advantageously,

in the presence of an inert organic solvent. Examples of tertiary baseswhich can be used, and which are generally present in the reactionmixture in an amount corresponding to .at least 10 percent by weight ofthe starting copolymer are pyridine, N,N-dimethyla'niline,triethylamine, N-morpholine, N-methyl piperidine and the like. Pyridineis the preferred tertiary base and can, if desired, be used insufiicient amount to act as solvent as well as catalyst for thereaction. Indeed, in a most preferred embodiment of the invention, thereaction is carried out with However, in place of the excess of pyridineas solvent, there may be used an inert organic solvent, i.e. an organicsolvent which does not enter into reaction 'with either reactant orinterfere in any way with the desired both, reactants in solution inpyridine.

course of the reaction. Examples of inert organic solvents the like.

dyestuff or azo coupler R H, is advantageously carried out at elevatedtemperatures, i.e. from about 50 C. to a about C., in order to achieve asuitable rate of reaction. The course of the reaction can be followed byroutine procedures, for example, by infrared spectroscopicexamination ofaliquots. The desired radiationsensitive polymer so obtained can beisolated from the reaction'product by standard procedures. Thus, thedesired product is generally present in the reaction product in the formof its salt formed by the tertiary amine catalyst with the free carboxygroups generated in the re action. Thus, the two reactions, taking placeat difierent locations in the molecule of the starting copolymer, can berepresented schematically as follows:

a b Ra (I: tertiary CHOH H-CHz- R0H amine Q 0 R: -CH-CH-( JHCHa- (boonoo [tertiary amine] tertiary --CHCH HCHz- R 11 mine 0 O R: CH-CH'(JH-CH2 [tertiary (v1) amimfl wherein R, R and R are as hereinbeforedefined.

For the sake of simplicity the reaction schemes shown vabove illustratethe opening of the anhydride ring in the starting copolymer in each caseso that the carbon atom a carries the moiety -COOR or COR wherein R andR have the significance hereinbefore defined, and the carbon atom bcarries the carboxylic acid-salt moiety. As will be readily appreciatedby one skilled in the art, the

anhydride moiety in the starting polymer can open in the reverse mannerso that the corresponding unit in the final product, in one or both ofthe cases, has the moiety OOOR or -COR on the carbon atom b and thecarboxylic acid salt moiety on the carbon atom a. It will be furtherappreciated by one skilled in the art that .the product obtained by theabove reaction will have a largely random distribution of the twopossible structures in the units in the chain of the final product. Itis to be understood that the specification and claims of thisapplication are not limited to polymers having only one of the twopossible structures in the recurringunit but are intended to encompassall possible combinations of structures within the polymer chain. Y

The radiation-sensitive polymer of the invention is accordinglyrecovered from the reaction product by acidifying the latter and, in thecase where no inert solvent was present, isolating the precipitatedpolymer by filtration or like means. Where an inert solvent has beenemployed in the reaction, the desired polymer is isolated f from thesolvent solution by precipitation with a solvent such as carbontetrachloride in which the polymer is insoluble or by evaporation of thesolvent in question. As will be appreciated by one skilled in the art,the number of anhydride moieties in the starting copolymer which will beconverted in the manner described above will depend on the total amountsand relative proportions of the copolymer and the two monomericreactants employed in the above reaction. Advantageously, the relativeamounts of alcohol ROH and dyestufi or azo coupler R H employed in theabove reaction are such that there are from about 0.2 mole to about 5moles of ROI-I for each mole of R H, i.e. the radiation-sensitivepolymer will contain from about 5 to about 0.2 of the recurring units ofFormula III for each recurring unit of Formula II. Preferably theproportions of ROH to R H in the above reaction are about 1 mole of thelatter for each mole of the former so that, for every recurring unit ofFormula II in the final polymer, there is one recurring unit of FormulaII'I.

Further, the relative molar proportion of starting polymer to thereactants ROH and R H is advantageously such that from about 20 percentto about 100 percent of the anhydride moieties present in the initialpolymer are converted to moieties of the Formulae II or III. Preferablythe relative molar proportions of the reactants are such that about 80percent of the anhydride moieties present in the initial polymer areconverted to moieties of the Formulae II or 111.

An alternative but less preferred method of preparing theradiation-sensitive polymers of the invention in which there is acombination of recurring units II and III in the polymer chain comprisescarrying out the above reaction between the starting polymer and thereactants ROH and R H stepwise instead of simultaneously. Thus, usingthe reaction conditions described above, the starting copolymer isreacted firstly with one of the reactants R-OH and R 'H and the productso obtained is reacted with the other of said reactants. The order inwhich the two reactants are employed is not critical.

Whichever of the two methods is employed in preparing theradiation-sensitive polymers of the above type, it is obvious that thedistribution of the various units of Formula II and III in the polymerchain will be largely random and not controlled.

The radiation-sensitive polymers of the invention which contain arecurring unit of Formula I are prepared by a modification and extensionof the above-described two step procedure. Thus, the starting copolymeris reacted with one of the two reactants ROH or R H under the reactionconditions described above whereby, depending on the relative proportionof reactants, one or more of the anhydride moieties in the startingcopolymer is converted to the tertiary amine salt of the correspondinghalfester or amide of Formula V or VI. The free carboxylic acid is thengenerated from the amine salt and said acid is then esterified oramidated, as the case may be, with whichever of the reactants ROH or R Hwas not used in the first step. Said esterification or amidation can becarried out in accordance with procedures well-known in the art.Illustratively, in the case of esterification, the alcohol and the acidare brought together at elevated temperatures, i.e. from about 50 C. toabout 150 C., in the presence of a trace of mineral acid such assulfuric acid, hydrochloric acid and the like and, advantageously, inthe presence of an inert organic solvent as hereinbefore defined.Preferably, the inert organic solvent is a solvent such as benzene whichforms an azeotrope with water and can thereby be used to remove'thewater eliminated in the esterification reaction and so accelerate therate of the latter. In the case of amidation, the free carboxylic acidmoieties in the intermediate polymer are converted to the correspondingacid chloride by reaction with thionyl chloride and the like, and theacid chloride is reacted with the appropriate amino dyestuff oraminophenol under conditions generally employed in the preparation ofamides.

However, when the desired recurring unit of Formula I contains an amidegroup, said group is preferably introduced in the first of the two stepsby opening the anhydride ring of the starting copolymer by reaction withthe appropriate aminodyestutf or aminophenol. The second stage ofreaction would then always be esterification.

Just as in the case of the polymers of the invention having therecurring units of Formulae II and III, so in the case of the polymerhaving the recurring unit (I), the latter unit can exist in twostructures depending upon the manner in which the anhydride ring in theunit (IV) of the starting copolymer opens. The product obtained by theprocess described above will have a polymer chain in which somerecurring units have one structure and some have the other. For the sakeof convenience this state of affairs is summarized by use of the singleFormula I for the recurring unit of said polymer. It is to be understoodthat all the various possible structures are within the scope of thisinvention.

As will be appreciated by one skilled in the art, the percentage ofanhydride moieties in the starting copolymer which are converted tomoieties of the Formula I in the above-described preparation, can becontrolled by using the appropriate molar proportions of reactants.Further, it is possible to obtain radiation-sensitive polymers of theinvention which contain a mixture of recurring units of Formula I andFormula II or III or even a mixture of all three types, by employing anamount of esterifying or amidating agent in the final step, which isless than the stoichiometric amount required to convert all the freecarboxy groups in the intermediate polymer. The radiation-sensitivepolymers of the invention having a combination of all three recurringmoieties of Formulae I, II, and III in polymer chain can be obtained bysubjecting to amidation or esterification some, but not all, the freecarboxy moieties in the radiation-sensitive polymers of the inventionprepared as described above Which have recurring units of both FormulaII and Formula III in the chain thereof.

The amino dyestuffs represented by the formula R H, wherein R is asabove defined, can be any of the basic dyestuffs, listed in ColourIndex, Second Edition, vol. 1, pages 16174653, 1965, published jointlyby The Society of Dyers and Colourists, Bradford, Yorkshire, England,and The American Association of Textile Chemists and Colourists, Lowell,Mass., which dyestuffs contain an amino group but have no other groupsuch as hydroxy or amino in the molecule, which would enter intoreaction with the anhydride moiety of the starting polymer. Typical ofsaid dyestuffs are: crystal violet, methylene blue, malachite green,auramine 0, basic fuchsin, Aniline Yellow, Disperse Orange 3, DisperseBlack 7, Disperse Red 13, Disperse Red 9, Vat Red 33, Mordant Violet 6,Phenylene blue, Disperse Orange 11, Natural Orange 6, Natural Brown 7,and Natural Yellow 12.

The primary hydroxy group containing dyestulfs represented by theformula R H, wherein R is as above defined, can be any of thosedyestuffs well-known in the art which contain a single primary hydroxygroup but which contain no other active group such as hydroxyl, aminoand the like, which would enter into reaction with the anhydride moietyof the starting polymer.

Illustrative of said dyestuffs containing primary hydroxyl groups areNatural Orange 6 (2-hydroxy-1,4-naphthoquinone), Natural Brown 7(8-hydroxy-1,4-naphtho quinone), Natural Yellow1,2[2-(p-hydroxyphenyl)-l,4- naphthoquinone]; the Z-hydroxyethyl ethersof said compounds (obtained by reacting the hydroxy dyestuffs such asthose named above with 1 molar proportion of ethylene oxide); DisperseRed 13, also known as Palacet Scarlet B [2-chloro-4-nitro-4'-(N ethyl Nhydroxyethylamino) azobenzene] and like compounds obtained by reactingbasic dyestuffs containing a secondary amino group (see Colour Index,supra) with 1 molar proportion of ethylene oxide.

Those radiation-sensitive polymers of the invention hav ing a recurringunit of Formula I or Formula III, or a combination thereof, in which thegroup R represents the residue of an aminophenol azo coupler, can bereacted with a diazonium salt to convert said group R to a dyestuffmoiety. The conversion can be carried out either be fore, or after, theradiation-sensitive polymer is bonded to a substrate as will bedescribed hereinafter.

The reaction of the azo complex moiety with the diazonium salt can becarried out using the procedures-and diazonium salts discussed andexemplified in Encyclopedia of Chemical Technology, Ed. Kirk-Othmer,Second Edition, 1963, vol. 2, page 870 et seq. Any of the Azoic DiazoComponents listed in Colour Index, supra, vol. 2, pages 2571-2612 can beused in the diazotization step.

The maleic anhydride copolymers having the recurring unit (IV) which areemployed as starting materials in the process of the invention arewell-known in the art; see, for example, Encyclopedia of ChemicalTechnology, supra, vol. 8, pages 685 et seq. and vol. 11, page 652; U.S.Pats. 2,424,814 and 2,047,398. These copolymers can be obtained in awide range of molecular weight, namely, from about 100,000 to about1,250,000. As will be appreciated by one skilled in the art, the chainlength of the starting maleic anhydride copolymer will remain unaffectedby the conversion to the ester and amide polymer having recurring unit(I), (II), or (III) although the overall molecular weight of the polymerwill increase according to the number of anhydride moieties in thestarting copolymer which are converted to ester and amide moieties.

In general themolecular weight of the radiation-sensitive polymers ofthe invention will be within the range of about 100,000 to about2,000,000. Said polymers are, for the most part, resinous solids whichare soluble in polar solvents such as acetone, methyl ethyl ketone,tetrahydrofuran, dioxane and the like, from which they can be cast asfilms as will be described in more detail hereinafter.

The radiation-sensitive polymers of the invention having the recurringunits (II) and (HI) can, by virtue of the free carboxylic acid groupstherein, exist in the form of salts such as the salts with alkali metalssuch as sodium, potassium, lithium and the like, alkaline earth metalssuch as calcium, strontium, barium and the like, ammonia and organicamines. These salts are, in general, possessed of reasonable solubilityin water, a property which renders them valuable in certain applicationsof the polymers of the invention as is discussed below. The freecarboxylic acid moieties of the polymers of the invention having therecurring units (II) and (III) can be converted to the correspondingsalts by procedures well-recognized in the art; for example by reactingthe polymer in solution in a polar solvent with an aqueous solution ofthe corresponding base. The amount of base employed can be such as toneutralize only one, or more than one, or all, of the free carboxylicacid groups in the polymer chain.

The alcohols R--OH, wherein R is as hereinbefore defined, which areemployed as starting materials in preparing the radiation-sensitivepolymers of the invention, are readily prepared by reacting theappropriate dial HOA-OI-I wherein A has the significance hereinbeforedefined, with the appropriate isocyanatobenzenesulfonyl chloride offormula:

(SOzCl):

OCN-

. (VII) wherein R", x and y have the significance hereinbefore defined.There is thus obtained the corresponding sulfonylchloride intermediatehaving the formula:

(S0201)x HO-A-O-li-NH- R", (VIII) which intermediate is then reactedwith sodium azide to convert the sulfonylchloride moiety tosulfonylazide and yield the desired alcohol ROH.

In carrying out the above synthesis of the starting alcohol ROH, thediol HOAOH and the isocyanatobenzenesulfonyl chloride (VII) are broughttogether under conditions well-known in the art for the reaction ofalcohols and isocyanates. Advantageously, the reactants are broughttogether at ambient temperatures, i.e. of the order of 20, C. to 25 C.,in the presence of an inert organic solvent, as hereinbefore defined.The reaction mixture is maintained below about 50 C., after thereactants have been brought together, in order to avoid reaction of thehydroxy groups in the diol with the sulfonyl halide moieties in, theisocyanatosulfonyl chloride. Such reaction would clearly give rise toundesired by-products.

If desired, the reaction between the diol and theisocyanatobenzenesulfonyl chloride (VII) can be carried out in thepresence of'a catalyst. Illustrative of such catalysts are thoseconventionally used in promoting the reaction between a hydroxyl groupand an isocyanato group, such as, for example triethylamine,triethylenediamine, N,N, N',N-tetramethylethylenediamine,N,N,N',N-tetraethylethylenediamine, N-methylmorpholine, Nethylmorpholine, 1,l,3,3-tetramethylguanidiue,N,N,N,N'-tetramethyl-l,3-butanediamine, stannous octoatc, dibutyltindilaurate and the like. I

The intermediate hydroxyalkyl carbamate (VIII) so preparedvcan, ifdesired, be isolated from the reaction mixture, for example, byevaporation of solvent, and purified, for example, by recrystallization,before conversion to the desired alcohol ROH. However, it is generallynot necessary to isolate the compound (VIII) prior to its .conversion tothe desired alcohol and, indeed, in most instances the reactionproductobtained in the reaction of the diol and the isocyanatosulfonyl chloride(VII) can be employed without any further treatment in the conversion tothe ultimate alcohol. Illustratively, the reaction product obtained inthe above process, comprising the compound (VIII) in solution in inertorganic solvent, is treated, without any purification, with theappropriate amount of sodium azide, i.e. one mole of sodium azide foreach SO Cl group in the compound (VIII). The reac-.

evaporated to dryness. The alcohol so isolated can be purified byrecrystallization or like procedures prior to being employed in thesynthesis of the polymers of the invention.

The isocyanatobenzensulfonyl chlorides (VII) which are employed asstarting materials in the preparation of the alcohols ROH are, for themost part, well-known in the art and are obtained by phosgenation of thecorresponding known aminobenzenesulfonic acids using conventionalprocedures such as that described by Alberino et al. J. Polymer Science,vol. 5, pages 3212-13, .1967.

As set forth previously, the novel radiation-sensitive polymers of theinvention are useful for ayaricty ofpurposes. For example, said polymerscan be used as a means of chemically bonding dyestulfs to the surface ofa variety of substrates such as paper, cotton, and like cellulosicmaterials, metal, glass and the like, as well as polymeric substrates,such as polyolefins, polyurethanes, polyamides, polyesters, polyacetalsand the like, which arenot normally receptive to such dyestuffs. In thisparticular use of the polymers of the invention, acoating of the latteris applied to a part, or the whole, of the surface of the substrate tobe treated. The coating is applied advantageously by dissolving theradiation-sensitive polymer of the invention in a polar solvent, such asexemplified above, and spreading the solution on the substrate using theappropriate spreading means. The coated substrate is then exposed to anappropriate source of radiation either thermal or actinic, necessary toactivate the polymer of the invention. A wide variety of sources ofthermal and/or actinic radiation can be employed. Such sources includecarbon arcs, mercury vapor lamps, fluorescent lamps, argon glow lamps,photographic flood lamps, and tungsten lamps. Preferably, the source ofradiation is one which generates ultraviolet light of wavelength withinthe range of about 250 nm. to bout 390 nm.

If desired, the irradiation of the coated substrate can be performedimagewise; that is to say, a negative of an image to be produced on thesurface of the substrate is interposed between the coated substrate andthe source of radiation. The radiation-sensitive polymer in thoseportions of the coated substrate receiving the radiation is activatedand becomes chemically bonded to the surface of the substrate. Thechemical bonding of the radiation-sensitive polymer to the substrate isbelieved to take place by degradation of the sulfonazido group or groupsin the moieties of said polymer to yield a nitrene radical which entersinto interaction with --CH bonds in the substrate. This suggestedreaction mechanism is, however, offered by way of explanation only andis not intended in any way to define or lirnt the scope of the presentinvention.

Where the polymer, in the coated substrate obtained as described above,contains the residue of an azo coupler (i.e. the recurring units I orIII contain R as the residue of an aminophenol azo coupler) the coatedsubstrate can then be treated with a diazonium salt solution to convertthe azo complex residue to a dyestulf moiety. The application of thediazonium salt to the azo complex can be accomplished in anyconventional manner, for example, by dipping the coated substrate in abath of diazonium salt solution or applying the latter to the substrateusing a roller, sponge or the like.

As will be readily appreciated by one skilled in the art, the aboveprocess, for chemically bonding basic dyestuffs to polymeric substratesnot normally receptive to such dyes, can be adapted to a variety ofdyeing and/or printing techniques. For example, the printing ofadvertizing and like matter on polymer films can be accomplished readilyon a continuous basis by passing a continuous sheet of said filmsuccessively through zones in which the film is coated with aradiation-sensitive polymer of the invention, the coated film is exposedimagewise to activating radiation from an appropriate source, and theunexposed coating is removed by solvent washing. The latter step can beaccomplished by washing the exposed film with the solvent employed toaccomplish the original coating or with a like polar solvent.Alternatively, where the light sensitive polymer contains free carboxygroups, the unchanged light sensitive polymer can be removed from thefilm by washing with an aqueous solution of a base such as sodiumcarbonate, sodium hydroxide, ammonium hydroxide and the like. In thecase where the polymer of the coating contains an azo coupler in placeof a dyestuff, a final step, of contacting the exposed coating with adiazonium solution, is added.

In yet another use of the novel radiation-sensitive polymers of theinvention having the recurring unit (I), the latterjare employed asthecomponents of a photo-resist system. For example, the said polymers canbe used in the photographic reproduction and printing arts to produceprinted masters as follows. The polymer (I) is dissolved in a polarorganic solvent such as those exemplified above and cast as a film on anappropriate substrate such as paper, metal and the like film supportsnormally employed in the reproduction art. A negative of the image to bereproduced, e.g. lined, screened or half-tone negatives, ordiapositives, is interposed between the supported film so obtained and asource capable of producing radiation necessary to activate theradiation-sensitive polymer. The polymer in those portions of thesupported film exposed to the radiation is thereby bonded to thesubstrate. The polymer in the unexposed portions of the film can then beremoved by washing with polar solvent, or, in the case of polymerscontaining free carboxy groups, by washing with an aqueous solution of abase as described above, leaving the exposed polymer bonded to thesubstrate in the form of a positive image corresponding to the negativeused in the irradiation step. Said image has high resistance to solventsand mechanical stresses and can be used to advantage as a master fromwhich to reproduce copies of the original.

In a similar manner photoresist systems produced from the radiationsensitive polymers of the invention can be used in other photoresistapplications such as in the printing of microcircuitry and relatedapplications which involve production of an image, in the formof bondedpolymer, on a metal substrate such as copper, followed by removal, inpart or in toto, of the uncoated metal by etching. Essentially the sametechnique as that described above in the production of printed mastersis employed in the formation of the polymer image on the substrates.

The following preparations and examples describe the manner and processof making and using the invention and set forth the best modecontemplated by the in-ventors of carrying out the invention but are notto be construed as limiting.

Preparation 1.To 50.4 gms. (0.8 mole) of ethylene glycol in 500 ml. ofacetonit'rile is added a solution of 43.2 gms. (0.2 mole) of 4isocyanatobenzenesulfonyl chloride (prepared by the method of L.Alberino et al., supra). The addition is accomplished over a period of10 minutes with stirring and cooling at circa 2 C. to 8 C., and themixture is then allowed to stand at room temperature until the NCO bandstretching has disappeared in the infrared spectrum of an aliquot of thereaction mix-v ture (approximately 30 minutes). To the mixture soobtained is added 13 gms. (0.2 mole) sodium azide and the resultingmixture is stirred for one hour at room temperature. The sodium chloridewhich has precipitated is removed by filtration and about percent ofsolvent is evaporated from the filtrate under vacuum. Water is added tothe remaining filtrate to precipitate the water insoluble product. Thelatter is separated by filtration, washed with water, and dried undervacuum at room temperature. There is thus obtained 52 gms. (91 percenttheoretical yield) of a white crystalline powder identified by infraredand NMR spectrometric examination as 2-hydroxyethyl4-azidosulfonylcarbanilate and having a melting point of C. to 118 C.Recrystallization from acetonitrile gave white crystals having a meltingpoint of 120 C. to 122 C. (Fisher-Johns method); 124 C. (DSC method).

Analysis. Calculated C H N O S (percent): C, 37.76; H, 3.46. Found(percent): C, 37.60; H, 3.73.

Using the above procedure but replacing ethylene glycol by 1,3-propyleneglycol, 1,4-butanediol, 1,3-pentanediol, 2,3-hexanediol,1,5-heptanediol, and 2,2-dimethyl- 1,6-hexanediol,2,5-diethyl-1,-6-hexanediol there are obtained:

3-hydroxypropyl,

4-hydroxybutyl,

3-hydroxypentyl,

3-hydroxy-2-rnethylpentyl,

S-hydroxyheptjil,

6-hydroxy-2,2 dimethylhexyl, and

6-hydroxy-2,S-diethylhexyl 4-azidosulfonylcarbanilate, re-

spectively.

Example 1.A mixture of 1.7 g. of a poly(maleic anhydride co-methyl vinylether) [having an average molecular weight of 250,000: Gantrez AN-ll9],1.57 g. of Palacet Scarlet B, and 1.43 g. of Z-hydroxyethyl4-azidosulfonylcarbanilate was dissolved in 30 ml. of anhydrouspyridine. The resulting solution was heated at 80 C. for 12 hours. Theproduct so obtained was evaporated to drywherein one of P and Q ishydrogen and the other is a and l in 2 of the said recurring units aremoieties of the formula:

OCH;

-GHCH 11-4111 oon 003 wherein one of A and B is hydrogen and the other Afilrn was cast by spraying a small sample of the above 7 polymersolution on a polyethylene sheet using a whirler. The plate wasirradiated by exposure for minutes to'a mercury arc lamp (Hanovia typeSH). When the irradiation was complete, the film was found to be bondedto thev polyethylene substrate and was highly resistant to removal byvarious abrasive forces and was insoluble in acetone and other polarsolvents.

Example 2.-Using the procedure described in Example 1 but replacing thepoly(maleic anhydride co-methyl vinyl ether) there employed by apoly(maleic anhydride costyrene) having an average molecular weight of100,000, there was obtained the corresponding modified poly-. (maleicanhydrideco-styrene) in which approximately 1 in 2 of the recurringunits in the chainwere moieties having the formula:

wherein one. of P and :Q is hydrogen and and 1 in 2 of the saidrecurring units werenioieties of v the formula:

CeHs

wherein one of A and B is hydrogen and the other -'is lnbut replacingtheZ-hydroxyethyl 4-azidosulfonylcar-' banilate there used by equivalentamounts of 3-hydroxypropyl, 4-hydroxybutyl, 3-hydroxypentyl,3-hydroxy-2- methylpentyl, S-hydroxyheptyl, 6-hydroxy-2,2-dimethylhexyl,and 6-hydroxy-2,S-diethylhexyl'4-azidosulfonylcar; banilate,respectively, there are obtained the corresponding" modified copolymersof maleic anhydride and methyl vinyl ether. V,

Example 4.-A filmwas cast from the solution of light the other is 'solidwhich separated was isolated by filtration, dried,

'chain are moieties of the formula:

sensitive modifiedzcopolymer of Example :1, on polyethm: ylene foil assubstrate. On top of, the film was, placed a master representinganegative of apattern of ,dots to be, reproduced. The film was exposedfor 2 minutes to .the

, light emitted by a Hanovia type SH mercury arc, theplane of exposurebeing at a distance of 15 cm. from the lamp. The exposed film wasdeveloped by immersion with agitation for one minute in a mixture ofacetone and N,N--- dimethylformamide (100:1 by volume). The image so,obtained exhibited a high degree of resolution.

Example 5.,-A mixture of 1.7 got a poly(maleic anhydride co-methyl vinylether) [having an average mo-. lecular weight of 250,000; GantrezAN-1l9], 0.55 g. of p-aminophenol, and 1.43 -,g. of 2-hydroxyethyl4-azidosul- I fonylcarbanilate was ,dissolved in.30 ml. of anhydrouspyridine. The resulting solution was heated at C.-,for

12 hours. .The product so obtained was evaporated to dryness and theresidue was dissolved in a mixture of equal and dissolved in 50ml. of amixture of acetone and methanol. There was thus obtained a solutioncontaining a photosensitive modified poly(maleic anhydride co-methylvinyl ether) in which 1 in 2 of the recurring units in the -jon'-cHB:oH=-.-j I O OP 00o wherein one of P and Q is hydrogen and the other isand l in 2 of the said recurring units have moietiesioif the formula:

' I I IOCQH:

' -CH-CH-CHCH2 wherein one of andIX is COO H and the other is -ooNn--o11A film was cast on a polyethylene substrate from the solution so.obtained. On top of the film was placed a master representinga negativeof a pattern of dots. to

be reproduced. The film was exposed for 2 minutes to the light emittedby a Hanovia type SH mercury arc, the plane of, exposure being at adistance of 15 cm. from the lamp; The exposure film was developed byimmersion with agi-. tation for 1 minute in a mixture of acetone andN,N-di-- methylformamide (:1 by volume). I 1

and found to have a darkred image, corresponding to the negativeemployed in the irradiation, bonded thereon,

The image was highly resistant to removal by abrasive forces and bysolvents.

We claim: t v v I 1. A radiation-sensitive polymer characterized by thesisting of (a) recurring units of the formula:

.I I TRIM, I Y (I:H cH-t H ;fCiiipresence of recurring unitsselectedfrom the class con- "whriii" R selected from the group consisting o e ra k'a am; r e lt a P iXa 'r as itss --COOR and the otherrepresents COR wherein R in each instance is a group of the formula:

(SOZNI) x wherein A is alkylene having from 2 to 6 carbon atomsseparating the valencies and a total carbon atom content of from 2 to10, R is selected from the class consisting of lower-alkyl and halogen,x is an integer from 1 to 2, y is an integer from to 2, provided thatx+y is not greater than 3, and the SO N group is in any of positions 3,4, and in the phenyl nucleus to which it is attached and at least one ofthe said positions 3, 4, and 5 is unsubstituted; and R in each instanceis selected from the class consisting of the residue obtained byremoving the hydrogen atom from the hydroxyl group of a dyestutf havinga primary hydroxyl group, the residue obtained by removing the hydrogenatom from the amino group of an amino-containing dycstutf, and theresidue obtained by removing a hydrogen atom from the amino group of anazo coupler; and

(b) a combination in the same polymer chain of recurring units havingthe formulae:

wherein one of X and Z represents COOH and the other represents COOR asdefined above, and

R2 CH-(3HlH-CHz wherein one of X and Z represents COOH and the otherrepresents COR as defined above; and wherein R in both instances has thesignificance defined above.

2. A radiation-sensitive polymer according to claim 1 wherein there ispresent a combination of recurring units having the formulae:

OCH:

CH-CH- H-CHr- OOP OOQ wherein one of P and Q is hydrogen and the otheris o -om-om-o- -Nn4-som,

and 5 OCH:

OH-CH- H-CHP wherein one of X and X is COOH and the other is CONHQOH 3.A radiation-sensitive polymer according to claim 1 wherein there ispresent a combination of recurring units having the formulae:

OCH;

--CH-CH H-OHz- (1001? 00o wherein one of P and Q is hydrogen and theother is 0 cm-cmwJLnnQsom OOH:

and CH-OH- H-CH: 00A 4100B wherein one of A and B is hydrogen and theother is CHr-CHz-NN=NNO2 'zHg References Cited UNITED STATES PATENTS2,948,610 8/1960 Merrill et al 96-33 3,016,306 1/1962 Mader et al117-333 3,230,201 1/1966 Hart et a]. 260-775 3,322,733 5/1967 Breslow260-793 JAMES A. SEIDLECK, Primary Examiner I. KIGHT III, AssistantExaminer US. Cl. X.R.

